1. Field of the Invention
The present invention relates generally to abrasive waterjet cutting and disposal of radioactive material. In particular, the present invention relates to systems and processes that separate waterjet abrasive material from high level radioactive material cut by an abrasive waterjet process to minimize the amount of high level radioactive material for handling and disposal.
2. Description of the Related Art
Abrasive waterjet cutting is a process where a high pressure water source is forced through a nozzle and mixed with an abrasive medium. The high speed jet of water is dynamically unstable and breaks into small droplets that accelerate the solid abrasive particles. This high velocity abrasive slurry micro-machines a workpiece by causing erosion, shearing and failure due to rapidly changing localized stresses. The workpiece particles and abrasive particles are mixed as a result of the cutting process.
The abrasive waterjet cutting process requires several times the mass and volume of abrasive particles to perform the cut than are removed from the workpiece in the kerf of the cut. Therefore, when cutting radioactive materials, the mixture of the abrasive particles and workpiece particles represents an increased volume of high level radioactive material that must be handled and stored.
Waterjet cutting processes are commonly used during the dismantling of nuclear reactors. For example, waterjet cutting processes are often used on radioactive components, such as nuclear reactor internals, vessels, and other activated or contaminated materials and structures. These radioactive components are normally cut using a waterjet cutting process in a reactor vessel cavity, spent fuel pool or other underwater pool or cell.
The mixture of waterjet abrasive material and high level radioactive material removed during waterjet cutting processes is considered unstable unless it is captured and stored in high integrity containers. The handling and storage of large volumes of such radioactive material is expensive and takes up a large amount of the limited space available for storing the material. Thus, there is a need for a system that separates non-radioactive abrasive material from the high level radioactive material so that the materials can be disposed of separately, thereby reducing handling concerns and disposal costs.